Securing cores in brush channel elements



April 12, 1960 J. v. MERTES 2,932,051

SECURING CORES IN BRUSH CHANNEL ELEMENTS 1 Filed Aug. 7, 1956 FICLZ FIG.3

FiG- 9 INVENTOR. JOS'P/l M MKU'A'S United States Patent SECURING CORE-S IN BRUSH CHANNEL ELEMENTS Joseph V. Mertes, Catonsville, Md., assignor to Pittsburgh Plate Glass Company, Allegheny County, Pa., a corporation of Pennsylvania Application August '7, 1956, Serial No. 602,533

2 (Ilaims. (Cl. 15182) This invention relates to a brush construction involving channel-like backing elements and bristles replicately disposed about a securing core in said element and it has particular relation to safety clips for securing the core in the backing element.

Brush strip elements have heretofore been constructed by forming a backing channel from a strip of metal and inserting the butts of bristles in the channel. Usually, the bristles are held in place in the channel by filamentary cores of wire or other suitable material about which the bristles are replicately folded, and the side walls of the channel backing element are then convergently bent or the edges thereof are crimped to grip the bristles and to retain the core. Such construction is relatively inexpensive and has enjoyed extensive commercial use, especially in rotary brushes such as are formed by spirally winding an elongated strip of such brush element upon a suitable power driven mandrel.

One serious disadvantage of such construction resides in the fact that the crimping pressure upon the bristles and the core of a brush unit of the foregoing construction does not always sufficiently securely hold them in the channel and under the effects of repeated fiexures of the bristles in service and especially under the influence of centrifugal force upon the assembly, the core may be loosened or even dislodged completely thus allowing a part of, or, all ofthe bristles to escape. thereby prematurely terminating the life of the brush. At the same time, the loosened material which may often be traveling at high speed,'may create a hazard to the operator.

In order more securely to hold the assembly against the effects of centrifugal force and of flexing of the bristles, brush units have heretofore been constructed having tabs struck at intervals in the side walls of the backing element. These tabs are adapted to be bent transversely across the channel as teeth which bear upon the top or outer perimeter of the core and thus hold the latter in place. However, the formation of the teeth in such operation may seriously weaken the side walls of the channel. vMoreover, the operation of striking the tabs usually leaves raw edges upon the teeth and the flexing of the bristles in contact with these edges may 'cut' them, thus hastening the deterioration of the brush.

It has also been proposed to provide liner elements for the channel backing element, these liner elements being provided with teeth holding the cores in place. This con- "struction has the advantage that the side walls of said "edges likely to cut the stock during service of the construction L This invention comprises the provision of simple and inexpensive safety clips of U-shape or other appropriate of appropriate thickness and inserted at intervals in the channel of a brush strip in such manner as firmly to lock the filamentary core from displacement. If these clips are formed from round wire or from wire of ovoid section, or are otherwise so formed as to eliminate angular edges and burrs, the cutting or chafing of the stock is eliminated or at least much reduced. The side walls of the channel backing element are in no wise weakened and the added metal is very slight so that there is but little reduction in the bristle population in a brush formed from the brush strip element.

For a better understanding of the invention, reference may now be had to the accompanying drawings in which like numerals refer to like parts throughout and in which:

Fig. 1 is a fragmentary section of a brush of rotary, power-driven type and formed from a bristle strip em bodying the principles of the invention;

Fig. 2 is an end view of a rotary brush formed by spirally winding a brush strip constructed in accordance with the principles of the invention;

Fig. 3 is a fragmentary side view of a portion of a strip as shown in Fig. 2 but being upon a larger scale;

Fig. 4 is a sectional view taken substantially upon the lines IV-IV of Fig. -3 illustrating a safety clip embodied within the provisions of the invention; I

Fig. 5 is a sectional view upon the line V'-V of Fig: 6

" showing a bristle retaining core which is provided with a modified form of safety clip;

Fig. 6 is a side view of the construction as shown in Fig. 5;

Fig. 7 is a sectional view of a slightly modified form of the construction of the form shown in Fig. 4;

Figs. 8 and 9 are views illustrating different sections of wire from which the safety'clips of this invention may be formed. I g

In the construction as illustrated in Fig. 4 of the drawings, a brush "strip is formed comprising a channel-like element 25 comprising a bottom or web portion 26 and side walls 27 and 28 integrally formed therewith and enclosing a bristle-securing core 29 upon three sides. The core usually is of mild steel, aluminum, brass, or the like, but could be of plastic or other organic material of relatively high tensile strength.

The bristle material is indicated at 30 and preferably is of the double ended type and is replicately disposed with'the bight portions of the bristles enclosing the core so that the latter acts as a securing element for the material. The bristle material may be of tampico, synshape, such as may be formed from wire or from tape thetic plastics, steel wire, brass wire or the like.

The channel element 25, as shown inFigs. 1, 2, 3 and 4, preferably is formed of an elongated tape of adequate width to provide the web portion 26 and the side walls 27 and 28 thereof. It may be of any convenient length, but in many instances, is of such length as to admit of the winding of the strips formed therefrom in spiral form to provide a cylindrical or fmstoconical brush comprising a single piece of the brush bristle strip.

' The sidesof the channel strip as illustrated in Fig. 4 are inwardly inclined or convergent, to provide gripping pressure upon the brush bristle material and the core 29. However, in most instances, it is impracticable so to incline the side walls as to provide a channel of lesser width than the diameter of the securing core disposed in the channel at least without excessively reducing the amount of stock secured within the channel. In the absence of the safety clips to bedescribed, opportunity would be afiorded for possible loosening of the core and the brush bristle material.

Means more positively to lock the core within the channel, in the embodiment of the invention as shown in Fig. 4, comprises a safety clip 31 which as illustrated is initially of inverted U-shape or invertedstaple shape Comprising a bight portion 32 and legs or branches 33. This clip preferably is formed of wire of steel, aluminum, brass or the like of fairly heavy gauge and the zone of anion between the bight portions and the branches may be at least partially inwardly inclined so that the core can not be displaced therefrom without positively springing the branches apart. The densely packed layer of bristles at L between the ends of the clips and the side walls prevent the ends of the clip from being spread apart. It will be apparent that the upper extremities of the branches may be terminated below the edges of the side walls, though in the construction as shown, it is extended some- What above said side walls. They could also be turned down over the edges of the side walls to grip the latter and to p ide spaci g e eme s b en n gu u turns of the b ush stfipa r If p efe re the s de o t safe y clip could also pres i ct y aga n t th sid l s I n 8- The co e .2 s sti l posit e y cke n h nel 25, i the clip and core 29 are of sufl'iciently heavy wire and the side walls 27 and 28 are sulficiently convergent.

I This construction is illustrated in Fig. 7 which essentially corresponds to Fig. 4 and to which the same numbers, but with prime markings, are applied.

The clips may be formed of wire or stock of various sectional shapes, as for example round, as indicated at S in Fig. 8, or fiat, o r ovoid with rounded edges as indicated at S in Fig. 9. Manifestly, other shapes than illustrated may be employed. However, it is desirable that the stock from which the clips are formed be free of angular edges and burrs which might tend to cut the bristle material in the channel.

The safety clips may be distributed at any convenient distance along the channel element as may be found desirable for purposes of adequately locking the securing core in the channel. The interval between clips may be, for example, from a fraction of an inch, egg. /2 inch, to 2 or 3 inches or even more. Naturally, the shorter the spaces between clips, the more securely is the core locked in position. However, the use of an excessive number of clips is uneconomical andtends to reduce the amount of stock which can be secured in a given channel.

In the operation of forming a brush bristle strip in accordance with the provisions of the present invention as illustrated in Figs. 1, 2, 3 and 4, it will be apparent that the insertion of the bristle stock and the securing core, together with the forming of the channel element 25, may follow conventional procedures or other appropriate techniques such as might be employed in the absence of the safety clips 31. The only departure in techniques need be in the mounting of the clips. A satisfactory method of performing the latter operation involves disposing the clips in position upon the wire constituting the core 29 at or shortly prior to the time the wire is pressed down upon the bristle stock and the side walls 27 and 28 are pressed or formed to grip the "latter material.

As the channel is formed and the bristle material is inserted and locked by the core, the latter may conveniently be wound upon a mandrel to spiral form as indicated in Figs l and 2. Such spiral may be mounted upon power-driven mandrel or roller 35 as shown in Fig. 1 and may be clamped in place as for example by means of end plates, one of which is indicated at 36. The plate is slidable upon the mandrel and is engaged by friction washer 37. Pressure to force the member 36 against the spiral comprises a nut 38 threaded upon a shoulder portion 39 of the mandrel. The mandrel may be terminated by a bearing portion 41 mounted to rotate in any convenient bearing construction.

The opposite extremity of the mandrel 35 maybe. provided with other pressure means (not shown) ,as for instance a similar end plate and actuating mechanism or by m an o a su ta e ol ar or other con t ct n secured upon the mandrel to provide a backing against which the spirally wound brush strip may be pressed by the plate 36 to secure it in position. The ends of the spiral may also be secured to the roller 35 by screws or other clamping means (not shown).

In Figs. 5 and 6 of the drawings, is illustrated a modified form of securing clip which in this instance, comprises a piece of wire of appropriate gauge turned as indicated at 42 to form a split ring extending about the core 2%. These split rings may be disposed at appropriate intervals along the core. If desired, they may be held from slipping by soldering, brazing, welding or in any other convenient manner. The rings may be mounted upon the wire constituting the core before the latter is received by the brush manufacturer. Obviously, the manufacturer could also apply the collars or rings as a preliminary operation to the manufacturer o t brush s r ph i .2 i 'l vi t e rings 2 is r ed there: along is mounted in a channel element with bristle mate: rial folded thereabout. The construction essentially corresponds to that indicated in Fig. 4 of the drawings, except for the substitution of rings 42 for clips 31.

The forms of the invention as herein shown and def scribed are to be considered as being by way of illustra ,tion. It will be apparent to those skilled in the art that numerous modifications may be made therein without departure from the spirit of the invention or the scope of the appended claims.

I claim:

1. A rotary brush comprising a channel strip back ing element having convergent sidewalls and a web connecting the sidewalls, said backing element having double length filamentary bristle material with the bight portions thereof disposed in the channel of said backing element, said backing element being spirally wound to circular form, a filamentary core disposed in the bight portions of the bristle material and locking the bristle material in the backing element, a series of longitudinally spaced safety locking devices disposed along the turns of thecore and comprising pieces of wire curved substantially completed around the core within the bight portions of the bristle material, said locking devices being carried upon the core independently of the channel backing element, portions of the bristle material looped about the filamentary core being densely packed between the safety locking devices and the convergent sidewalls of the backing element to hold said safety locking devices from displacement from the channel in said backing element. i

2. A rotary brush comprising a channel backing element having convergent sidewalls and a web connecting the sidewalls, said backing element having double length filamentary bristle material, the bight portions of which are disposed in the channel of the backing element, said backing element being spirally wound to circular form, a filamentary core disposed in the bight portions of the bristle material and locking the same in the channel of the backing element, a series of safety locking devices holding the core in the channel and comprising pieces of wire curved substantially completely around the core and engaging the core at their inner perimeters substantially completely around the perimeter of said core, and engaging at their outer perimeters with the sidewalls of the backing element to lock the filamentary core from displacement from said element.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 25932 051 April 12,, 1960 Joseph V, Mertes rlng correctlon and that the said Letters Patent should read as corrected below.

Column 4c line 42, for "completed" read completely Signed and sealed this 11th day of April 1961 (SEAL) e-5T W SWIDER M, j ARTHUR W. CROCKER Attesting Oflicer ctmg Commissioner of Patents 

